Embryology Flashcards
What will epiblasts in a 3-week embryo become?
Ectoderm.
How many days after fertilisation does implantation occur?
7-8 days.
What does the blastocyst divide into?
Embryoblast (inner cell mass) and Trophoblast (outer cell mass).
What does the embryoblast divide into?
Epiblast and Hypoblast = bi-laminar disc.
What does the trophoblast divide into?
Cytotrophoblast (inner) and Syncytiotrophoblast (outer).
How is the primary utero-placental circulation established?
Lacunae form in the syncytiotropohoblast and maternal blood enters.
What happens in the third week of embryonic life?
Gastrulation - formation of a tri-laminar embryonic disc.
What part of the tri-laminar disc are somites formed from?
Paraxial plate mesoderm.
What part of the tri-laminar disc is the circulatory system formed from?
Lateral plate mesoderm.
What does the ectoderm form?
CNS, PNS, skin, posterior pituitary and sweat glands.
What does the endoderm form?
Respiratory tract, GI tract, urinary tract, auditory tube, liver, pancreas, thyroid and parathyroid glands.
What happens in the 4th week of embryonic life?
The flat tri-laminar disc folds into a cylindrical embryo.
What layer of the tri-laminar disc does the epiblast form?
Ectoderm.
What cells does the epiblast give rise to?
Amnioblasts that line the amniotic cavity.
What cells does the hypoblast give rise to?
Cells that line the blastocyst cavity.
